Distance-type relay with limited directional discrimination



Jan. 17, 1950 s. L. GOLDSBOROUGH 2,495,166

DISTANCE-TYPE RELAYS WITH LIMITED DIRECTIONAL DISCRIMINATION 2 Sheets-Sheet 1 Filed Dec. 29, 1945 2/ AAA 1 4e ,1 4; ,5/ 45 9' h 49 m fi'gj.

12 4/ n, 2' 52 -z i. .5

03 'I II WITNESSES: INVENTOR ATTORNEY Jan. 17, 1950 Filed Dec.

S. L. GOLDSBOROUGH DISTANCE-TYPE RELAYS WITH LIMITED DIRECTIONAL DISCRIMINATION 2 Sheets-Sheet 2 4 it? M WITNESSES:

m" l 74w 7 INVENTOR ATTORNEY Patented Jan. 17, 1950 ISTANCE-TYPE RemwwrrmmMrrnD DIRECTIONAL DISCRIMINATION-w Shirley L. Goldsborough, BaskiirgBidga-NQJL, as I Signor t hflusefilfilectriceGorporation, East Pittsburgh, Pa, a corporation of Pennsyl- Vania Application December 29,1945, SeriaFNo. 638,355

' claims.

My present invention relates to distance-type relays for protecting alternating-current transmission-lines againstfa'ults."

An object of my invention is to produce a distance-relay with a limited directionahdiserimination, having a long reach," in both directions, along the,- iault-ohmsdlne or, axis and, having a short reach for currents 90 out of phase with the fault-currents; or along the: directional axis.

More generally-statedfitis -'an"object"of my 10,-:

invention to provide a relay having a responsecurve which is elongated along the faulteaxis, and constricted along the directional, axis, in the region of the origin.

In many relay-applications, as incarrierecur 1513' rent high-speed relaying, it is very desirable to have a third-zone distance-element -"which; can see faults in either direction along: thefault axis, but having a limited response to load-ohms and to synchronizing-ohms. impedance-relay (Z3) as has been common prior to my present, invention, the center of the-v-impedance-circle has been displaced from the origin,"

with the result that it has been necessary to utilize a separate Z3 element to look in the re verse direction to start' carrier. By my present invention, I provide, an impedance-element in which, when the impedance-circle center is displaced from the origin, it'is'displaced in exactly opposite directions at thesame -ti mez Even aside from carrier current rel-as appli cations in whichvthellachoithe ability of a'third- In the third zoneg-wizone impedancee element"to. :see in'- both direc tions is a disadvantage, a displaced-centers relay in which the-circ1ercenterrdisplacement'isgreater:

than the circle-radius has a further disadvantage by reason of the factthattthe circle does not in clude the origin of: the ooordi-nate axes of, line-" resistance R and line-reactance X, so that the relay will not respond to close-in faul-ts,of 'low ohms. A modification of my invention makes it possible to give the response-curveroithe relay,

a bulge or protuberance which encircles the origin. 1

A still further refinement of my improved relay provide 'a' distance type' relay utilizing rectified current andvo-ltage responsivequantities" to" pro- In thei;accompanying drawing, Figures 1 anddz aracurvm-dfigrams showingsome; of, the; possi:--:

bilities: of myxrelay-adjustments',g and Figs. 3,, 4.:

andzfiare diagrammatic; views .;of 401113111135 and :apparatuss embodying; my? invention: 11131131111685 air, ferent forms oi embodiment-..

ciples of the invention, and then the specific illusnative forms of; embodiment, thereof.

lietius-assume three derived current-resp onsiv'e alternating voltages having instantaneous values,

where I is the R. M. S. value of the line-current,

and"0 .is theapower factor angle-of theline, counting 0 positive for lagging power-factors, and countingqMi; 2LBJI'IdTM3 :positive when they make their derivedwvoltages :11, 2'2; and-:13, lead"; thev linebeing scalar:quantitiesgreater than zero;

Now: let. us: assume. three derived voltage-reasponsive alternating voltages having; instana taneous values,

L Where'E is the R. M. S. value of the line-voltage,

makes; it possibleto distortz the response-curve] in'such direction astoenahle it the better'to;-re.;-- spond to faultshavinga considerable fault'fre- I sistance. v,

A generally statedobject ofiny invention istccounting N1, N2 and N3 positive when they make their derived voltages in, v2 and 1):; lead the linevoltage /2 E sin wt; m, m, m and E being soala i' qnantitiesgreater than zero.

Now let us assume that each of the voltages h r and m is perfectly rectified by a separate double- De wave'rectifi'er; that each of the voltages i2, is, v: and:missperfectlyrectified by a separate single- I waver. rectifier that the direct-current component of each of the six rectified voltages is eliminate'd, and; that-the:un-smoothed-out alternatmg-current components of the six rectified volt- I shall first explain 17118: mathematical prin,

ages are added, to produce a. restraint-voltage v:

for a difierential relay. The harmonic analyses 2'], cos (yt+ Y) dt== (9) given in Jolleys Alternating Current Rectifica tion, New York, Wiley, 1926, pages 32-33, show y that the instantaneous value of the restraint- 27 ha 8111 (yt-l-Y) dt=0 voltage is (210-1) (2Ic+1) 1 2m 2 I cos 2k(wt B+M m /Is1n(wt0+M1) 2 1)(2k+1) 1 2nd? cos 2k(wt+N n; 2 E sin (wt+N;)+- [2- 1 2m /I cos 2k(w:-0+M,) -m Is1n(wt0+M;) T (2k 1)(2k+1) (7) where k is the kth term of an infinite series of Remembering also that terms which are added. 2r 1 1 When this restraint-voltage U1 is applied to (yH- 005 (MH- the restraint-coil of the difierential relay, let us 1 I assume that the restraint-coil flux hr leads the sin (y Sin (ZIH impressed voltage Or by an angle T, and has a 1 1 magnitude which is h times the magnitude of the cosx cos y cos (:c--y) cos (z-l-y) impressed voltage 1):; h being a scalar quantity 1 1 greater than zero, and the value of the angle T Sin making no difference in the operation of the remm y 2 cos (x y) 2 cos (2+2!) lay. The instantaneous value of the restraint- 1 1 coil flux or field-strength is 5 5111 (76+?!) (11) +w2 -naesin (wi+N;+T)+m I sin (wt-0+M5+T)] (s :The square of this instantaneous restraintand putting flux hr is a measure of the restraint-force. As =M N we are interested only in the average value Hi S a: M N

of the instantaneous restraint-force hr our cal- 2 2 culations are much simplified, because we can (12) drop all terms containing cos (yt-l-Y) or I sin we find, from Equation 8, that the average value (yt-i-Y), because of the restraint-force is 2 7 v [m n EI sin (M -N 6)+mm EI sin (9M1+N3)] 13 In Equation 13, 1 1 1- 1. 1

' cos 2km cos 2x cos 4x cos 690' cos 8%,

cos 10x 008 12a: cos 14a: cos 16x 9801 20449 38025 17 62,500

cos 18a: 1043 2 9; L

The values of ,f(a:) and [;f(9:)] for different values of the angle (1:, are shown in the table.

Now let, usassume that the differentiaL relay-a 40 has an operati g cojl flux. or fleld strength hav- Tabze iv n g an 1nstantaneous yalue h /2.18m (wt-+ U) (18) a d having. an average squarewalue 01 om t- 45 ing force (again divided by the constant, W) of Degrees Degrees Degrees Degrees 0 180 180 300 11685 .01365 H 2 175 185 355 +.114r 01316 l (.19) 170 190 350 +1084 01115 h 165 195 345 +.0982 0004 100 200 340 +.0852 --.0072e. where g'is a scalar quantlty greater than; zero, 25 155 205 335 +0097 00486 nd U i 1 h k if 150 510 33(5) +832? 50 v? A ty 9118?, W 89 ma BSM O (11 .211 6 35 145 15 3 40 9 140 9 1 150 00225 n opera Ion 48. 136.1 8 45., 13,5: 22.5 3115 OM21 000018 The relay W111 operate when the restrainlng 130 230 10 10229, -.000s2 force 1s.-1es s-;tha r; the-operatmg force; or when; as 23% 822; 88 23 5 .7 v 7 g5 2 4 To determine the -vre1ay-operat1on in terms of O 1 v 2651 275: .1058 01119 the 11ne Impedance Z 1t 1s necessary to note that 00 270 270 -.1073 --.01151 the numer-1ca1;;va1 ue of the; el1ne-1mpedance 1s v nee. a. E: Rewmtmg Equatlon 13, we find the average 2 (21) estraintdogce (dividedhy the constant; 713;), to be 2,496,166 2 8 This is a scalar quantity,-and it is always posunderstanding that I am not limited, of course, itive, because E and I are both scalar quantities. to the particular settings chosen for illustration.

both always positive. Z represents a length The simplest case is when I utilize only the two which is to be measured, from the pole or origin, derived voltages i1 and or, which are double-wave on the radius vector which thus becomes a line rectified.

representing an impedance-angle or 'power-fac- In this case, I

tor angle. The radius vector or impedance-line mz=mz=nz=ns=0 (32) is at an angle 0 m the polar axis or the line Substituting from Equations 27, 2a and 32 in representing lme'l'eslstance Equations 24, 25 and 26, we find, from Equation Substituting from Equatimls 19 and 21 in 23, that the balance-point of the relay is at any the inequality rearranging the terms, and line-impedance which satisfies the equation =8.558%f(0-S i8.558% /[fl0-SOI -0.01365 +0.07208gflum, (33) dividing through by I we find that the relay the values of fix) and '(:c)] being shown in will respond when the table,'for dilferent values of the angle :10, and

Z2+bZ+ Q (22) only positive values of Z being valid solutions of whence the equation.

/m Fig. 1 shows four curves, 11, 12, 13 and 14, T showing the various values of the line-impedance where Z, corresponding to the balance-points of the re- +0.424.41 m,m sin (M M )+m,m sin (M,--M,)] 26 1 1 6 1f l lay, at four settings of the relay-constants of 1r '4k*-"'1 1 (1e 2 Equation 33, as follows:

0.81057=% 23) For curve 11, L? Li s5 s= M-N =75 and 5.279 mm==0.2 34 0.29736 2 (29) 1 1 1) g/ l o.42441.== (30 3 curve 1e21i4= (31) 1 =7s n 5- 7 g/ m1= 8 f (:n) is as defined in Equation 16, and 2 must curve always be positive. Only positive values of Z are valid solutions of the inequality (23). S,= (M N )=75 and 5.279g /h m1= 1.5 (36) At the balance-point of the relay, the inequality-sign, in Equation 23 becomes an equality- For curve 14,

sign, The locus of the line-impedance Z, at

various power-factor angles 6, is usually plotted S =(M N )=75 and 5.279g=/hm =4 (37) on rectangular coordinates representing the lineresistance R and the lagglng-power-factor line- The scale of ohms or distance has not been inreactance X, yielding a separate response-curve dicated in Fig. 1, because that scale may be made for each relay-setting. anything desired, by the proper choice of the The performance of the relay represented by value of mi/m. the Equation 23, and the efiects of some of the Equation 33 expresses the line-impedances Z,

variables in the relay-adjustment, will best be at the balance-points of the relay, in polar coillustrated by several concrete examples, with the ordinates, in terms of the angle a:=(0-S1), using *factbr lirie-reaottnc I I or the relay-eharacter s ics'dn re'ctaii'gular coor- -It is -Tii-1s'line representsa la in p r men) tin le the fault ifiipedarice angle of a"tra'iis'mission lin'e.

faddirfg'a nne' repiesestme the lagging p we ave-a representatisn 'di'ri'aites tax 'assndwmn-Frg.- 1.

"reach" of the relay, cr me matinee "to which it respondsflis sh by the intercept "of "the response-curve on 'th'e rau1t=axis-FoFn "It to the enemas shown bytl'ie equati'en r's ense-eurv or he 'ria-y their i *two separate loops,-*or' ellipse arrestures; his "ted by the line-fault axis FOF, as shifiwn inc'iirve ll of Fig. 1. The ratio of the two fault-axis intercepts is Z, 1 +2.2cs /hm1 the response-curve (if the r i'a has an our- =glass shape, its iengtnmong the flinefau'lt aids Forf'fand its waist-along the direetiohtn a is Don' which passes through t e origin at 'ht angles to "T n e ons e r ser fthis'blass "snows at is and *M in Fig. The rach'f of tneie'iay, *erthe'triterce t arisen-trainees h J 'xis FOF is zr'as ntercept the by putting The ratio of these two intercepts is -t" matter-1 p y directly "fespohsive tothe ratio of the relay-constants m1 and 111, which are defined in Equations 1 and 4. It is also alfeotedbythemagnitudes of theeiirrent-res'ponse coeflicient m1 and the ratio ofthe relay-constants g and h, which determine "the flux-strengthyor ratio of coil-turns to magnetic reluctance, "of the operating'and restraining j'coils respe tively, "as defined "in Equations 18 and 8. It is thus clear that the shape of the curve can be controlled by varying the currentresponse coefficient m the {operatin -coil coeflicient g, "or therestraint-coil coefficient hi; and after the shape has been determined, the size of the curve, or thescale of impedance-ohms to be applied to it, can be controlled by varying the voltageres'ponse e'oelfieient 'm, if it is :d'e'sired to retain the selected "shape undisturbed; or the size-scale or distance-calibration could alternatively be controlled by varying the current-response coefficient 1121, if a simultaneous change in the intercept Z or Za is unobjectionable Examination of the-harrhonic analysis of the 'full-waverectified restraint-voltage 'Ur, as given in Equation '7, and the resulting derivations'yvill show that the seoondharmonic term, containing the factor cos 2(ugt-l-Ni), is the largest harmonic, and that this harmonic could be segregated and utilized alone-or, in general, the relative magnitudes of the difierent harmonics could be cansiderably distorted-without qualitatively changing the resultsto anymate'ria1 extent, "mares changing the magnitudes of the various constants and the magnitudes of the effects which they have on the relaycharacteristics. h I

The relay-characteristics can'be changed by superimposing, on the full-wave-rectified corn- 'po'nent, one or more ghalf-wave-rectified components of either the line-current, or the linevoltage, or both. fFourillustra'tive case's willbe given, and plotted in Fig. 2, with the understanding that thesepar'ticulfar cases are only illustrative, as the inequality (23) is perfectly general, "and applicable to all possible values of all 'of the constants (or variable factors of the relay) with} in the limitations which 'were indicated when the inequality (23) was first written.

In generaLthe effect of adding a'half-waverectified'component, *by assigning finite valuesto m2, n2, ms and/or 513, is to make the response curve of the relay unsymmetrical with respect to the directional a-Xis -D-"D'. If m2 and m are "equal to each other, and if the angle S2 is equal to S1, (or to S1'l"180-)-, the effect 'of'a'd din'g the "m2 and m components "to the curves shown in Fig.1 is to make the portion of the curve above (or-below) the mien- 13' larger, and the "other portion smaller, without destroyingthe sy m'i'netry with respect tothe fault-line axis FOF. If vii: and 'n: are equal to each other, and if the angle S3 is equal to S1- plusa small "angle, the effect is to move the-fau=lt-axis bodily to-the right, while slightly decreasing its inclination to the i i-axis, and at the same tim'eii'ncreasing the reach" or the relay for internal faults.

The internal-fault intercept, on the fault-axis OF, is found by putting (-Si) =0. It is where z z l.62114(4m n +m n +2m n +2rrzm g 52 The internal-fault intercept, on the fault-axis OF", is found by putting (0S1)=180. It is K Z,'=B /B +K, (53) where man:

The differential-axis intercept, on the axis DOD, is found by putting (0-81) =90 or 270. It is The value of K2, and hence g /h' mi determines the magnitude of the differential-axis intercept Zd, which is one-half of the width of the waist of the hour-glass-shaped curve.

The relative magnitudes of the two fault-axis intercepts, Zr and Z'r, or, in other words, the reaches of the relay, for internal and external faults, respectively, may then be adjusted to any desired value by the proper choice of mznz, which determines the magnitude of the quantity which is added to 0.11685 to make B2, for the into-theline-looking intercept Zr, this same quantity being subtracted from 0.11685 to make B3, which enters into the expression for the out-of-the-protectedline-sectionlooking intercept Z'r.

Two illustrative curves, l5 and I6, ar plotted, in Fig. 2, for the values of Z shown in Equation 47, that is, for a relay in which the restraint- -winding current is made up of a full-wave-rectifled current-responsive component 12211, a full- Wave-rectified voltage-responsive component mE, a half-wave-rectified current-responsive component mzI, and a half-wave-rectifled voltage-re sponsive component nzE, under the special conditions expressed in Equations 43.

Curve l5, in Fig. 2 is chosen to illustrate a case 12 in which it is desired for the relay to have a very small reach along the directional axis DOD, a long forward-looking reach along the faultaxis OF, corresponding to a long length of the protected line-section, and a shorter reach m2=0.5m1, and nz=0.5nz (56) Curve H5, in Fig. 2, is chosen to illustrate the manner in which my relay may be adjusted to have a response-curve which is elongated along the fault-axis OF,-so as to be sensitively and selectively responding to currents having a powerfactor approximating the impedance-angle, S1, of the line, while not responding to power-load currents, or out-of-step or switching surges, and at the same time the response-curve is elongated, 0r bulged, near the origin 0, so that the curve encircles the origin, so as to make sure that th relay will respond to zero-impedance bus-faults at the relaying station. This is a very useful property, never before attained in a distance-responsive relay except with saturated current-transformers which have given special curve-distortions only when the line-current has been exceptionally high.

The relay-constants or adjustments, necessary to obtain a curve of the type shown at [6 in Fig. 2, are obtained by assigning a small value to B3, and solving Equation 54 for the value of m2/m1, which was assumed to be equal to nz/m, for purposes of symmetry and ease of calculation. This determines the valu of the coefiicient of cos (0S1) in Equations 49, which is the term which changes from positive to negative when the curve circles around the origin in the reverse-current direction. Various small values of K2 may then be tried, to determine the relative magnitudes of the three critical intercepts'Zr, Zr and'Zd, to determine the relay-constants which will produce the desired relay-characteristics. In curve it, the constants are in addition to the conditions indicated in Equations 43.

Curves l1 and I8, in Fig. 2 have been drawn to illustrate the manner in which a still further, very much wanted, distortion, or departure from a true circle, is obtained in the relay-characteristics. Here, the half-wave-rectified currentand voltage-responsive components, mzI and ME, have been utilized, with an angle, S:=M3N3=S1-10, for the sake of illustration in a concrete example. This shifts the curve in such manner as to enable the relay to respond to faults having considerable fault-resistance. In curve l1, this shifting-effect is made more pronounced than in curve l8, by

- assigning larger values to ms/mi and 113/711. In

both curves, the magnitudes of the m2 and 112 components have been adjusted to make the external-fault intercept Z'r have any desired value relative to the internal-fault intercept Zr. Thus, in curve H, the m and 112 components are utilized to make Zrlarger, which is done by reversing either the current-component 1222 or the voltagecomponent n2, so as to be opposite to the eifects in curves I5 and I6. Then a value of .if the adjustments are symmetrical, or, in general, to elongate the response-curve along the fault-axis. Thus, if only voltage were utilized on the back end, opposing the pull of a currentcoil on the front end of the relay, the responsecurve of the relay would be the well-known circle, with its center at the origin. Heretofore, it has been possible to displace the center, in one direction, from the origin, by vectorially adding an alternating-current current-component to the alternating-current voltage-component on the back end of the relay. By rectifying both the current and voltage components, before combin- I ing them on the back end of the relay, the impedance-circle center is, in effect, displaced in opposite directions at the same time. The rectification renders the relay insensitive to 180 reversals in current, but leaves it responsive to 90 shifts, particularly with the full-wave rectification obtained by the m1 and 111 components alone. It is to be noted that un-smoothed-out rectification is utilized, and that the direct-current components of the rectified waves are substantially eliminated.

By adding an unrectified fundamental sinewave component of each of the current and voltage-waves, to the full-wave-rectified components, it is possible to change the duo-directional symmetry of the full-Wave-rectifiedresponse, while retaining the effect of a response curve which is elongated along the fault-ohms axis and constricted along the directional axis, near the origin. One of the means for introducing such an unrectified fundamental current or voltage wave-form is to utilize a single-wave-rectified component, m2 and m, or m; and m, or both. Thus, in Equation 7, it is seen that the halfwave-rectified components, having the coefficients 1212, no, m3 and 113, have terms including the sine of a time-function of the type (wt-l-Y), which is an unrectified component. I desire my derivations and my illustrated apparatus to be symbolic of any means for introducing such unrectified components onto the full-wave-rectified components which are expressed, in Equation 7 by the infinite series Since an alternating current having a magnitude 11111 and a phase-displacement (+M1) with respect to another wave, has an in-phase component, miI cos (0+M1), and a quadrature-phase component, q'mil sin (0+M1), the phase-angle (0+M1) and the magnitude-coefficient m1 may be, in effect, adjusted indirectly, by separately controlling or adjusting the inphase coefficient m1 cos (0+M1) and the outof-phase coefficient m1 sin (-0+M1). Also, since the two half-Wave-rectified components m2 and ms, or m and m, are treated in the same way by the half-wave rectifiers, the two alternating currents having the coefiicients m2 and ma could be combined before rectification, and then rectified with-a single half-wave rectifier, and the same applies to the, voltages having the coefficients no and 713.

These principles are illustrated in the alternative form of construction shown in Fig. 4, wherein the six alternating-current components m1I4 (-0+M1) 'mzIg (0+M2) maI; (-0+M3) nrE 4N1, nzEgNz and naELNs, as previously de- 16 condensed into four, namely (R1I+7'X:I), (RzI-I-il'Xzl), (RaE-l-a'XaE) and (RlE-l-a'xlE), where.

R1=m1 cos (-0+M1) ('12) Thus, in Fig. 4, the line-current transformer 22 energizes four adjustable transformers GI, 62, 63, 64, which in turn energize the resistance R1, the reactance X1, the resistance R2, and the reactance X2, respectively. The sum of the resistance-drop R11 and the reactance-drop y'X1I is utilized, in lieu of the drop across the resistor 24 in Fig. 3, to produce the full-wave-rectified A. C. component appearing across the outputresistor 28, as in Fig. 3. The drops RzI-I-(I'Xzl are utilized, in lieu of the drop across the resistor 25in Fig. 3, to produce the half-wave- 25 rectified A. C. component appearing across the output-resistor 34, as in Fig. 3.

In Fig. 4 also, an adjustable potential-transformer G5 is utilized to energize the serially connected tapped resistance R3 and tapped reactance X3, and an adjustable potential-transformer 66 is utilized to energize the serially connected tapped resistance R4 and tapped reactance X4. The

drops (R3E+7'X3E) and (R4E-I-jX4E) energize the output-resistors 28' and 34' in a manner a which will be obvious from the drawing and the preceding explanations. Although the adjustments are different, it is obviously possible, by the proper choice of the eight variables, R1, X1, R2, X2, R3, X3, R4 and X4, in Fig. 4, to obtain the same kinds and sizes of response-curves, as with the apparatus which was exemplified in Fig. 3, and which was mathematically analyzed hereinabove.

In the field of distance-type relays with unrectified currents and voltages, it is known that the same types of responses can be obtained by multiplying two quantities (AD+BI) and (CE-l-DI) in a torque-type or product-responsive relay, as by opposing D 1 with the square of (AE-i-BI) in a differential relay, where the superposed dots indicate complex numbers. The same thing is true in my use of rectified quantities to change the relay-characteristics as previously described. The product of the sum of the infinite series representing the rectified quantities All and BI, multiplied by the sum of the infinite series representing the rectified quantities CE and 151 is not different, in kind, from the square of either sum. In either event, the result involves the function f(x) which is shown in the table, and various functions such as sin :c and cos an, very much in the manner shown in Equation 17, but with different coefficients and angles. In a a product-type relay, the balance-point is found by putting the product or torque equal to zero.

Without carrying out the precise mathematical calculations, which follow from the principles .already enunciated, I wish it to be understood that my general principle of utilizing rectified current-responsive and voltage-responsive quan- ..tities is applicable also to product-type relays as Well as to differential relays.

, Thus, in Fig. 5, I illustrate a wattmetric or v V product-type relay .1 I, having make-contacts l 2, scribed and illustrated in Fig. '3,"have been and two coils'13'and 14 for producing the fluxes energies which are to' be'multiplied. In: general, such. a

relay develops a torque equal to the product of the two fluxes (or quantities) timesa function of the angle between them, and this observation applies separately to each term of the product,

when (as here) the product is the resultant of the algebraic sum ofap-lura'lityof product-terms.

In Fig. 5, one coil 731s energiz'edin response to&

a full-wave-rectified current responsive voltage,

miI4(-9+M1), and a-ful1-wave rectified volt age-responsive voltage, n1E4N1, either with or:

without the addition of one'or more pairs of halfwave-rectified quantities 1112f; (0.+M2) and nzENa- The othercoil 14 is energized in the same-way, with thesubscripts changed to 3and4 instead of 1 and 2, the difiterent subscripts indicating, in general, different magnitudes.

Fig; 5 is believed to be necessary, corresponding numerals being utilized in so far as applicable,

thenumerals being applied mainly" to the energizing circuits for on1y'thec0il'13, theother coil, 14, being energized by identical apparatus, as

shown, except for different adjustments of the constants.

I claim as my invention: -1. A distance-responsive alternating current relay, comprising a relay-meanshaving at leasttwo magnetizing-means for producing at least two separate relay-fluxes and having iiux-re-- sponsive force-producing means for developing, from-said fluxes, a-responseto predetermined impedance values, in combination with line-ener-- gized energizing-circuitmeans *f or 'energiz-ingthe respective magnetizing rneans of therela-y, the energizing-circuit means which energizes the magnetizing-means for'producing at least'a predeterminedone-of said relay fiux-es being a com posite' energizing-circuit means including at least two line-energized circuit-means for carrying at least two derived alternating-currentrelayingquantities, at leastone of-sa'id Quantitiesbei-ng" responsive to a line-current, at least another one of said quantities'being responsive to" a 'line voltage, said composite energizing-circuit-meansalso including separate transformation means for deriving, from each of said relaying-quanti--- ties, an alternating 'voltage which is substantiallyfree of a direct-current component'a'nd which includes at'least adouble-pfrequency harmonic of the relaying-quantity, said composite energizingcircuit means and its associated 'mag-netizing means including, in their combined-structures,- meansfor causing the-resultant'flux to-be responsive to avectorial combinationof the voltages which are thus derived by the several' transformation-means.

2. A distance-responsive differential*alternat-- ing-current relay having a magnetizing-means for producing an operatingilux, a fluxresponsive force-producing means 'for producing an operatingforce responsive to the'operating flux, a'mag- Y netizing means for" producing a restrainingfiux; and a flux-responsiveforce-producing meansfor producing a restraining force responsive to the restraining flux, in' combinationwith line-ener gized I energizing-circuit means for energizing I the respective magnetizing-means of the relay, the

energizing-circuit means which energizes the magnetizing-means-for producing at least said restraining flux being a composite-energizingcircuit -means--including at least two line ener gizedcircuit-means' forcarrying at least twode- The: apparatus illustrated'in Fig. 5 utilizes amplitude' changers and phase-shifters, as already" fully described in Fig. 1, and-no further descriptionof rived alternatingscurrent relayingequantities, at

least one of said quantities being responsive to a line-current, at least another one of said quantities being responsive to a line-voltage, said com- 5 posite energizing circuit means also including separate transformation-means for deriving, from eachof said relaying-quantities, an alternating-voltage which is substantially free of a direct-current component and which includes at m least a double-frequency harmonicof the relaying quantity, saidcornposite energizing-circuit' ing-force respo-nsive to the operating flux, a'mag netizing means for producing a restraining flux,

and a' flux-responsiveforce-producing means for" ;,prodi1eing a restraining force responsive to the restraining flux, in combination with a line-energized energ-izing-circuit means for energizing the magnetizing-means for producing said operating flux being-exclusively responsive to a line-derived is current, and a composite line-energized energizing-circuit' means for energizing th magnetizing means for producing said restraining flux including at least two 1ine energized circuit-means for carrying at least twoderived alternatingggucurrent relaying-quantities, at least one of said" quantities being'r-esponsive toa line-current, at-

least'another one-of said quantities being responsive to a line-voltage, said composite energizing circuit means also including separate 4o transformation-meansfor derivingyfrom each of said relaying-quantities, an alternating voltage which is' substantiallyfree of a direct-current component and which includes at least a doublefrequency harmonic of the relaying-quantity, 4sz.-. said-composite energizing-circuit means and its associated"magnetizing-means-including, in their combined structures, means for causing the resultant-flux to be responsive to a vectorial combinationo-f the voltageswhich are thus derived SOWbythe several transformation-means.

"4. distance-type productresponsive alternetting-current relay having magnetizing-means for-producing-two diverse cooperating alternating magnetic fluxes, and flux-responsive force-pro 55sdi1cirig=-means forso utilizing said fluxes as to produce aitorque in-response to the product of said fluxes,--multiplied-by a functionof the angle between-the two-cooperating fiuxes, in combina- I tionwith two diverse line-energized energizing circui-t means for energizing the respective magnetizing-means, characterized by each of said line-energized energizing-circuit means including line-energized circuit-means for carrying at least two derived alternating-current o5 -relaying quantities,at least oneof said quantities' being responsive to a line-current, at least another one of said quantities being responsive to 'a-line-voltage, each of said line-energized energizingecircuit means also including separate w transformation-means for deriving, from each of itsrelaying-quantities, an alternating voltage which is substantially free of a directcurrent-component andwhichincludes at least ado'uble-frequency harmonic of the relaying- -75"quantity-;-each energizing-circuitmeans and its 19 associated magnetizing-means including, in their combined structures, means for causing the resultant flux to be responsive to the vectorial combination of the voltages which are thus derived by the several transformation-means.

5. The invention as defined in claim 1, characterized by the vectorial combination of voltages comprising a line-frequency fundamental-wave component of a current-responsive relayingquantity and a line-frequency fundamental-wave component of a voltage-responsive relaying quantity.

- 6. The invention as defined in claim 2, characterized by the vectorial combination of voltages comprising a line-frequency fundamental-wave component of a current-responsive relayingquantity and a line-frequency fundamental-wave component of a voltage-responsive relayingquantity.

7. The invention as defined in claim 3, characterized by the vectorial combination of voltages comprising a line-frequency fundamental-wave component of a current-responsive relayingquantity and a line-frequency fundamental-wave component of a voltage-responsive relayingquantity.

8. The invention as defined in claim 4, characterized by the vectorial combination of voltages comprising a line-frequency fundamental-wave component of a current-responsive relayingquantity and a line-frequency fundamental-wave component of a voltage-responsive relayingquantity.

9. A distance-responsive alternating-current relay, comprising a relay-means having at least two magnetizing-means for producing at least two separate relay-fluxes and having flux-responsive force-producing means for developing, from said fluxes, a response to predetermined impedance values, in combination with lineenergized energizing-circuit means for energizing the respective magnetizing-means of the relay, the energizing-circuit means which energizes the magnetizing-means for producing at least a predetermined one of said relay-fluxes being a composite energizing-circuit means including at least two line-energized circuit-means for carrying at least two derived alternating-current relaying-quantities, at least one of said quantities responsive to a vectorial combination of the derived alternating-current componentsof the recv tified quantities.

10. The invention as defined in claim 9, characterized by each of said separate rectifyingmeans being a full-wave rectifying-means.

11. A distance-responsive alternating-current relay, comprising a relay-means having at least two magnetizing-means for producing at least two separate relay-fluxes and having fiuX-re-v sponsive force-producing means for developing,

from said fluxes, a response to predetermined impedance values, in combination with lineenergized energizing-circuit means for energizing .60 tures, means for causing the resultant flux to be 7 plurality of diverse current-responsive alternat the respective magnetizing-means of the relay, the energizing-circuit means which energizes the magnetizing-means for producing at least a predetermined one of said relay-fluxes being a composite energizing-circuit means including at least two line-energized circuit-means for carrying a plurality of diverse current-responsive alternating-current quantities and line-energized circuitmeans for carrying a plurality of diverse voltageresponsive alternating-current quantities, said composite energizing-circuit means also including separate full-wave rectifying-means for separately rectifying one of said current-responsive quantities and one of said voltage-responsive quantities, separate half-wave rectifying-means for separately rectifying one or more of said current-responsive quantities and one or more of said voltage-responsive quantities, and means for deriving, from each of the rectified quantities, an alternating-current component or components including substantially none of the direct-current component, said composite energizing-circuit means and its associated magnetizing-means including, in their combined structures, means for causing the resultant flux to be responsive to a vectorial combination of the derived alternating-current components of the rectified quantitles.

12. A distance-responsive alternating-current relay, comprising a relay-means having at least two magnetizing-means for producing at least two separate relay-fluxes and having flux-responsive force-producing means for developing, from said fluxes, a response to predetermined impedance values, in combination with lineenergized energizing-circuit means for energizing the respective magnetizing-means oi the relay, the energizing-circuit means which energizes the magnetizing-means for producing at least a predetermined one of said relay-fluxes being a composite energizing-circuit means including at least two line-energized circuit-means for carrying at least two derived alternatingcurrent relaying-quantities, at least one of said quantities being responsive to a line-current, at least another one of said quantities being responsive to a line-voltage, said composite energizingcircuit means also including separate rectifying means for separately rectifying said quantities, and means for substantially removing the directcurrent component of the wave-form from each of the rectified quantities, said composite energizing-circuit means and its associated magnetizing-means including, in their combined structures, means for causing the resultant flux to be responsive to a vectorial combination of the redetermined one of said relay-fluxes being a composite energizing-circuit means including at least two line-energized circuit-means for carrying a eem reee in'g-rcurrent 'quantitieszand. linez-energizedrcircuit-J means for carrying a plurality of diverse voltage;

rent-responsive quantities andione or mOI'e"0fi1O saidvoltage responsive"quantities; and means for substantially removing; thedirect-"current com ponent of the wave-form from each of the rectified quantities, said composite energizing-circuit means and its associated magnetizing-means including, in their combined structures, means for causing the resultant flux to be responsive to a vectorial combination of the remainders of the several rectified quantities.

15. A distance-responsive difierential alternating-current relay having a magnetizing-means for producing an operating flux, a flux-responsive force-producing means for producing an operating force responsive to the operating flux, a magnetizing-means for producing a restraining flux, and a flux-responsive force-producing means for producing a restraining force responsive to the restraining flux, in combination with a line-energized energizing-circuit means for energizing the magnetizing-means for producing said operating fiux being exclusively responsive to a line-derived current, and a composite lineenergized energizing-circuit means for energizing the magnetizing-means for producing said restraining flux including at least two line-energized circuit-means for carrying at least two derived alternating-current relaying-quantities, at least one of said quantities being responsive to a line-current, at least another one of said quantities being responsive to a line-voltage, said composite energizing-circuit means also including separate rectifying-means for separately rectifying said quantities, and means for deriving, from each of the rectified quantities, an alternatingcurrent component or components including substantially none of the direct-current component, said composite energizing-circuit means and its associated magnetizing-means including, in their combined structures, means for causing the resultant flux to be responsive to a vectorial combination of the derived alternating-current components of the rectified quantities.

16. The invention as defined in claim 15, characterized by each of said separate rectifyingmeans being a full-wave rectifying-means.

17. A distance-responsive differential alternating-current relay having a magnetizing-means for producing an operating flux, a flux-responsive force-producing means for producing an operating force responsive to the operating flux, a magnoticing-means for producing a restraining flux, and a flux-responsive force-producing means for producing a restraining force responsive to the restraining flux, in combination with a line-energized energizing-circuit means for energizing the magnetizing-means for producing said operating flux being exclusively responsive to a linederived current, and a composite line-energized energizing-circuit means for energizing the magnetizing-means for producing said restraining flux including at least two line-energized circuitmeans for carrying a plurality of diverse currentresponsive alternating-current quantities and line-energized circuit-means for carrying a plurality of diverse voltage-responsive alternatingcurrent. quantities; said. composite. energizinge circuit :means also...includingrseparate full-wave a rectiiyingie'means 'for separately rectifying one of said current-responsive quantities andone of said rectifyingemeansdor separately rectifying one or more f. said: current-responsive quantities. and t 011E101 more :01 said: voltageeresponsive quantities, andin'eans 'for-zderivingyfr'ormeachrof the rectified: quantities, an 'alternating current component .or" components rincluding'substantially none of the direct-current component,.:.said composite ener voltage-responsive quantitieatseparate half -wave 2 gizingecincuit meansandiits associated magnetizeing-means including, in their combined structures, means for causing the resultant flux to be responsive to a vectorial combination of the derived alternating-current components of the rectified quantities.

18. A distance-responsive differential alternating-current relay having a magnetizing-means for producing an operating flux, a flux-responsive force-producing means for producing an operating force responsive to the operating flux, a magnetizing-means for producing a restraining flux, and a flux-responsive force-producing means for producing a restraining force responsive to the restraining flux, in combination with a lineenergized energizing-circuit means for energizing the magnetizing-means for producing said operating flux being exclusively responsive to a line-derived current, and a composite line-energized energizing-circuit means for energizing the magnetizing-means for producing said restraining flux including at least two line-energized circuit-means for carrying at least two derived alternating-current relaying-quantities, at least one of said quantities being responsive to a linecurrent, at least another one of said quantities being responsive to a line-voltage, said composite energizing-circuit means also including separate rectifying-means for separately rectifying said quantities, and means for substantially removing the direct-current component of the Waveform from each of the rectified quantities, said composite energizing-circuit means and its associated magnetizing-means including, in their combined structures, means for causing the resultant flux to be responsive to a vectorial combination of the remainders of the several rectified quantities.

19. The invention as defined in claim 18, characterized by each of said separate rectifyingmeans being a full-wave rectifying-means.

20. A distance-responsive differential alternat- 55 ing-current relay having a magnetizing means for producing an operating flux, a flux-responsive force-producing means for producing an operating force responsive to the operating flux, a

magnetizing-means for producing a restraining 60 flux, and a flux-responsive force-producing means for producing a restraining force responsive to the restraining flux, in combination with a lineenergized energizing-circuit means for energizing the magnetizing-means for producing said 65 operating flux being exclusively responsive to a line-derived current, and a composite line-energized energizing-circuit means for energizing the magnetizing-means for producing said restraining flux including at least two line-energized cir- 70 curt-means for carrying a plurality of diverse current-responsive alternating-current quantities and line-energized circuit-means for carrying a plurality of diverse voltage-responsive alternating-current quantities, said composite en- 75 ergizing-circuit means also including separate 23 fu1l-wave rectifying-means for separately rectifying one of said current-responsive quantities and one of said voltage-responsive quantities, separate half-wave rectifying-means for separately rectifying one or more of said current-responsive quantities and one or more of said voltage-responsive quantities, and means for substantially removing the direct-current component of the wave-form from each of the rectified quantities, said composite energizing-circuit means and its associated magnetizing-means including, in their combined structures, means for causing the resultant flux to be responsive to a vectorial com- 24 bination of the remainders of the several rectified quantities.

SHIRLEY L. GOLDSBOROUGH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 1 Number Name Date 2,393,983 Goldsborough Feb. 5, 1946 2,404,955 Goldsborough July 30, 1946 

